BIOS firmware for the ASRock B85M Pro3 motherboard, an Intel B85 chipset micro-ATX board; the trailing 3.40 most likely marks the BIOS version. It can be used to recover a board with a corrupted flash, by writing it to the SPI chip with an external programmer when the board cannot boot to update itself. Check that the image is a full dump rather than a vendor update capsule before programming. Back up the original contents and confirm the file size matches the flash capacity.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @biosarchive. Enginerys does not host this file.
How to open a .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.
Back up your own chip before writing any dump, and match the full board number and revision. Flashing guide →